1. Field of the Invention
The present invention relates to a linear stepping motor having its moving part, which steps in a straight line at a constant pitch conforming accurately to a pulse signal input and, in particular, to a linear step motor wherein exciting iron cores, provided with a plurality of field legs, are separated from each other in the direction perpendicular to the direction of movement of its moving part, and in which a magnetic field of a permanent magnet, and a magnetic field of an exciting coil are crossed at a right angle.
2. Description of the Prior Art
A linear stepping motor wherein exciting iron cores provided with a plurality of field legs are separated along the direction transverse to the direction of motion of a moving part is commonly known. In this type of linear stepping motor, a denticle, formed from a pair of exciting iron cores on the primary side or from a pair of non-exciting iron cores on the secondary side, must be secured integrally so as to offset the phase in the direction of motion of the moving part. Accordingly, in the case when, for example, a silicon steel plate is subjected to a punching press, and that silicon steel plates are laminated and a pair of exciting iron cores or a pair of unexcited iron cores are formed, at least two press molds are necessary to cope with the respective pair of exciting iron cores or a pair of unexcited iron cores, with the problem that the production cost is high.
In addition, conventionally, in the configuration in which a pair of exciting iron cores or a pair of unexcited iron cores are secured to a movable part or a stator, the magnetic resistance becomes large because of the configuration in which a component such as a bolt penetrates each iron core, so, in its turn the exciting current becomes large, giving rise to the problem that the temperature of the primary side becomes elevated.